package com.shidaimanong.demo.encypt;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * 学编程，关注：十代码农
 * 抖音、快手、B站、西瓜视频、今日头条
 */
public class AesDemo {
    //加密用的key
    private static final String key = "0123456789012345";
    //加密用的iv
    private static final String iv = "abcdefghijklmnop";

    /**
     * AES加密
     */
    public static String encryptAES(String data) {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            int blockSize = cipher.getBlockSize();
            byte[] dataBytes = data.getBytes();
            int plaintextLength = dataBytes.length;

            if (plaintextLength % blockSize != 0) {
                plaintextLength = plaintextLength + (blockSize - (plaintextLength % blockSize));
            }

            byte[] plaintext = new byte[plaintextLength];
            System.arraycopy(dataBytes, 0, plaintext, 0, dataBytes.length);

            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());  // CBC模式，需要一个向量iv，可增加加密算法的强度

            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
            byte[] encrypted = cipher.doFinal(plaintext);

            return AesDemo.encode(encrypted).trim(); // BASE64做转码。

        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * AES解密
     */
    public static String decryptAES(String data) {
        try {
            byte[] encrypted1 = AesDemo.decode(data);//先用base64解密

            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

            byte[] original = cipher.doFinal(encrypted1);
            String originalString = new String(original);
            return originalString.trim();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 编码
     */
    public static String encode(byte[] byteArray) {
        return new String(new Base64().encode(byteArray));
    }

    /**
     * 解码
     */
    public static byte[] decode(String base64EncodedString) {
        return new Base64().decode(base64EncodedString);
    }

    public static void main(String[] args) {
        String encrypted = encryptAES("123456");
        System.out.println(encrypted);

        String decrypted = decryptAES(encrypted);
        System.out.println(decrypted);
    }
}